208515-36-0Relevant articles and documents
A novel black tea pigment and two new oxidation products of epigallocatechin-3-O-gallate
Tanaka, Takashi,Matsuo, Yosuke,Kouno, Isao
, p. 7571 - 7578 (2005)
During tea fermentation, oxidation-reduction dismutation of a number of quinone metabolites of tea catechins yields numerous minor products, which make it difficult to separate and purify black tea polyphenols. In this study, epigallocatechin-3-O-gallate
Production of theasinensins A and D, epigallocatechin gallate dimers of black tea, by oxidation-reduction dismutation of dehydrotheasinensin A
Tanaka, Takashi,Watarumi, Sayaka,Matsuo, Yosuke,Kamei, Midori,Kouno, Isao
, p. 7939 - 7947 (2007/10/03)
Theasinensins A and D are B,B′-linked dimers of (-)-epigallocatechin 3-O-gallate connected through R and S biphenyl bonds, respectively, and are major constituents of black tea. Enzymatic oxidation of epigallocatechin 3-O-gallate produced dehydrotheasinensin A, and the structure was shown to be equivalent to an o-quinone of theasinensin A. When the aqueous solution of dehydrotheasinensin A was heated, theasinensin D was produced along with galloyl oolongtheanin. On the other hand, dehydrotheasinensin A was converted to theasinensins A and D along with oxidation products in phosphate buffer at pH 6.8 at room temperature. The results strongly suggested that theasinensins in black tea were produced by oxidation-reduction dismutation of dehydrotheasinensin.
